United States v. Truong Dinh Hung

629 F.2d 908 (1980)

Facts: Ds were convicted of espionage by transmitting classified docs and sought reversal of their convictions becaue of warrantless surveillance and searches. Ds argue FBI violated 4h amendment. No court authorization was ever sough or obtained for the installation of wire taps, for mail intercepts, etc. Ds thought “solely” for foreign policy reasons should be the test.

  • The government relied on a “foreign intelligence” exception to the Fourth Amendment. The FBI sought and received approval for the surveillance from the president’s delegate, the AG, – FBI says this approval is constitutionally sufficient to authorize foreign intelligence surveillance because of President’s constitutional prerogatives in foreign affairs (thus doesn’t need a warrant).

Issue: Whether the fourth amendment is violated when domestics are subjected to warrantless wiretapping for the purpose of foreign intelligence gathering.

Holding: Yes. The court now recognizes a foreign intelligence exception. However, because individual privacy interests are too important, the court provides a carefully limited exception:

(1) The government is only relieved from seeking a warrant when the object of the search is a foreign power, its agent or collaborators. Where there is no foreign connection, the executive’s needs become less compelling; and the surveillance more closely resembles the surveillance of suspected criminals, which must be authorized by warrant.

(2) The executive should be excused from securing a warrant only when the surveillance is conducted “primarily” for foreign intelligence reasons. (i.e. not for criminal prosecution).


  • Needs of executive are so compelling in foreign intelligence, as opposed to domestic security, that a uniform warrant would unduly frustrate the President in carrying out his foreign affairs responsibilities.
  • Executive branch has expertise (constantly aware of security needs) to make the decision whether to conduct foreign intelligence, as opposed to the courts unschooled in military affairs and diplomacy.
  • Crucial: Executive branch constitutionally designated as the pre-eminent authority in foreign affairs.
  • On July 20th, the investigation of D became primarily criminal, thus all evidence obtained through surveillance after that date must be excluded.

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